Separation of fulvestrant isomers

Abstract

The invention encompasses methods of separating the isomers of fulvestrant comprising placing a fulvestrant sample on a HPLC using a reverse phase column or chiral column; eluting the sample with an eluant having a first mobile phase and a second mobile phase; and collecting purified fractions of fulvestrant sulfoxide A or fulvestrant sulfoxide B from the column. The method provides fulvestrant sulfoxide A or fulvestrant sulfoxide B in 99.5% purity as determined by HPLC.

1 . A method of detecting fulvestrant diastereomers comprising 
 placing a fulvestrant sample on a HPLC using a reverse phase system;    eluting the sample with two mobile phases using a non-linear gradient having a first mobile phase and a second mobile phase; and    detecting the separate isomers by HPLC,    wherein the first mobile phase is water or an aqueous buffer and the second mobile phase is acetonitrile, tetrahydrofuran, or methanol.    
   
   
       2 . The method according to  claim 1 , wherein the fulvestrant sample is a mixture of fulvestrant sulfoxide A and fulvestrant sulfoxide B.  
   
   
       3 . The method according to  claim 2 , wherein the fulvestrant sample is a racemic mixture or a mixture enhanced in either fulvestrant sulfoxide A and fulvestrant sulfoxide B.  
   
   
       4 . The method according to  claim 1 , wherein the packing material of the reverse phase column is C8 (octyl), C18 (octadecyl), phenyl, pentafluorophenyl, or phenylhexyl.  
   
   
       5 . The method according to  claim 1 , wherein the packing material of the reverse phase column is C8 (octyl) or C18 (octadecyl).  
   
   
       6 . The method according to  claim 1 , wherein the first mobile phase has an initial amount of about 40% to about 70% by volume, and the second mobile phase has an initial amount of about 30% to about 60% by volume.  
   
   
       7 . The method according to  claim 1 , wherein the first mobile phase has a final amount of about 40% to about 0% by volume, and the second mobile phase has a final amount of about 100% to about 50% by volume.  
   
   
       8 . A method of separating fulvestrant diastereomers comprising 
 placing a fulvestrant sample on a HPLC having a chiral column system;    eluting the sample with two mobile phases using an isocratic solvent system having a first mobile phase and a second mobile phase; and    collecting purified fractions of fulvestrant sulfoxide A or fulvestrant sulfoxide B from the column,    wherein the first mobile phase is at least one C 5 -C 10  alkane and the second mobile phase is a C 3  alcohol.    
   
   
       9 . The method according to  claim 8 , wherein the packing material has the formula:  
     
       
         
         
             
             
         
       
     
   
   
       10 . The method according to  claim 8 , wherein the packing material of the chiral column is amylose tris(3,5-dimethylphenylcarbamate), β-cyclodextrin, cellobiohydrolase, selector R-(−)—N-(3,5-dinitrobenzoyl)-phenylglycine, or cellulose tris(3,5-dimethylphenylcarbamate).  
   
   
       11 . The method according to  claim 8 , wherein the packing material of the chiral column is amylose tris(3,5-dimethylphenylcarbamate).  
   
   
       12 . The method according to  claim 8 , wherein the column has a packing particle of a size of about 3 μm to about 10 μm.  
   
   
       13 . The method according to  claim 8 , wherein the column has a packing particle a size of about 5 μm.  
   
   
       14 . The method according to  claim 8 , wherein the first mobile phase is n-hexane, and the second mobile phase is isopropanol.  
   
   
       15 . The method according to  claim 8 , wherein the first mobile phase is present in an amount of about 75% to about 95% by volume and the second mobile phase is present in an amount of about 5% to about 25% by volume.  
   
   
       16 . The method according to  claim 8 , wherein the first mobile phase is present in an amount of about 85% by volume and the second mobile phase is present in an amount of about 15% by volume.  
   
   
       17 . The method of  claim 8  further comprising crystallizing fulvestrant sulfoxide A or fulvestrant sulfoxide B from the purified fractions by dissolving fulvestrant sulfoxide A or fulvestrant sulfoxide B in organic solvent to form a mixture and precipitating from the mixture fulvestrant sulfoxide A or fulvestrant sulfoxide B.  
   
   
       18 . The method according to  claim 17 , wherein the organic solvents is ethyl acetate or toluene.  
   
   
       19 . The method according to  claim 17 , wherein the mixture is heated to reflux followed by cooling to a temperature of about 0° C. to about 25° C.  
   
   
       20 . The method according to  claim 19 , wherein the mixture is cooled to a temperature is about 4° C.  
   
   
       21 . The method according to  claim 8 , wherein the fulvestrant sulfoxide A or fulvestrant sulfoxide B is 99.5% pure as determined by HPLC.